1. Field of the Invention
The present invention relates to air clays useful for toy models for play and learning for infants and young children as well as fabrication of prototypes of articles, and a method of manufacturing the same.
2. Description of the Related Technology
Recently, many technologies and approaches have been disclosed regarding artificial sand and clay for indoor use to replace natural sand and clay. Such approaches include, for instance: Korean Patent No. 231,408 which introduced a modeling composition for handcrafts; Korean Laid-Open Application No. 2004-361 which reported a method for preparation of viscous sand and a three-dimensional (3-D) learning method using the same; U.S. Pat. No. 6,235,070 which disclosed viscous sand and a process for production thereof; Korean Patent No. 598,001 which described a sand based mixture and a method of preparing the same; U.S. Pat. No. 5,873,933 which reported a mixture of malleable play materials with a crumbly soil-like feel for infants and young children; and Korean Laid-Open Application No. 2006-11,619 which proposed a naturally curable and functional clay emitting fragrance under pressure, etc.
Briefly, the modeling composition for handcrafts disclosed in Korean Patent No. 231,408 is produced by mixing water, salt, wheat flour, starch, stone powder, aluminum sulfate, oil, borax, magnesium chloride, sodium benzoate, titanium oxide and/or a dye together in desired mixing ratios, agitating and heating the mixture, and then, forming the mixture into a shaped product. This composition is easily kneaded into a paste using a small amount of water, advantageously has freezing resistance and controlled decay properties while maintaining a desired moisture content and favorable texture owing to addition of wheat flour and/or starch.
The viscous sand described in Korean Laid-Open Application No. 2004-361 which is used to repeatedly form a model and destroy the same by applying a desired force, is prepared by heating 80 to 90% by weight (“wt. %”) of sand at 75 to 90° C., adding 0.5 to 3.5 wt. % of carnauba wax to the hot sand and mixing at the same temperature so as to completely melt the wax and coat the sand with the molten wax, adding 8 to 12 wt. % of beeswax and 1.5 to 4.5 wt. % of lanolin to the coated sand and mixing while maintaining a temperature of 55 to 70° C. so as to completely melt the beeswax and lanolin and again coat the sand with the molten beeswax and lanolin, and slowly cooling the treated sand.
The viscous sand described in U.S. Pat. No. 6,235,070 and the sand based mixture described in Korean Patent No. 598,001 are common sand mixtures comprising sand particles and a binder, wherein the binder forms a coating on the sand particle and is at least one selected from a group consisting of beeswax, ceresin wax, microfine crystalline wax and a mixture of mineral wax and paraffin wax. This mixture may be used as a toy material, teaching material and/or construction material for architectural model design or landscape design especially for museums, aquariums, etc.
The mixture of malleable play materials with a crumbly soil-like feel disclosed in U.S. Pat. No. 5,873,933 generally includes a large amount of sand and an amorphous malleable binder, wherein the binder may include a soluble cellulose, polyvinyl alcohol, propyleneglycol, water, sodium borate, sodium carbonate, etc. The mixture exhibits a unique texture caused by the malleable binder combined with sand in large quantities as well as malleable and amorphous characteristics in a granular state.
Lastly, the artificial clay with natural curing properties and fragrance emitting function under pressure described in Korean Laid-Open Application No. 2006-11,619 is produced by combining polyvinyl alcohol and ethylene vinyl acetate as a base material with a filler including hollow type polyacrylonitrile powder having low specific density and heat expandable microspheres, adding a thickener, glycerin, a dry retarding agent (or a moisture retaining agent) and/or other additives to the combined mixture at room temperature, heating and mixing all of the materials together.